Just start today over. Focus on you. Eliminate contact. He is obviously seeing other people, I go back to you deserve more. You deserve to be with someone who only wants to see YOU.
Stop beating yourself up over this. Stop obsessing and look at the big picture. Why is the relationship what it is today? Is this really what you want for yourself long term? You don't have to live with this anxiety.
Start over today...you can do this!